Possible Clues:

• Last of seven, for many
• 'That'll always come before 17 across, perhaps (8)'
• Day named for the sixth planet from the sun
• Sun always rises afterwards
• Sat briefly for a time
• Samedi or Sabato or Samstag
• 9-to-5'ers await it
• The seventh of seven on a calendar
• Doctor Sara with duty for twenty-four period
• A day in the life of Radclyffe Hall